SUBMITTED BY

SAMEENA SHAMSUDEENI MDS

DEPARTMENT OF ORAL AND MAXILOFACIAL SURGERY

SURGICAL ANATOMY OF

MANDIBLE

largest and strongest bone of the face, serves for the reception of the lower teeth.

curved, horizontal portion, the body,

and two perpendicular portions, the rami, which unite with the ends of the body nearly at right angles.

RAMUS

BODY

ANATOMY OF MANDIBLE

CORONOID PROCSS

CONDYLAR

PROCSS

MANDIBULAR NOTCH

ANGLEOF MANDIBLE

MENTAL FORAMN

EXTERNAL OBLIQU E RIDGE

BUCCAL SHELF AREA

ALVOLAR PROCESS

LINGULA

MANDIBULAR FORAMEN

MYELO HYOID

LINE

DEVELOPMENT OF MANDIBLE

By around the 4th week of

intra-uterine life, five

branchial arches form in the

region of the future head

&neck.

THE BODY OF THE

MANDIBLE

These cartilages form the cartilaginous bar of the mandibular arch and are two in number, a right and a left.

The mandible is ossified in the fibrous membrane covering the outer surfaces of Meckel's cartilages.

Their proximal or

cranial ends are

connected with

the ear capsules,

and their d

istal

extremitie

s are

joined to one

another at th

e

symphysis by

mesodermal

tissue.

Meckel’s cartilage has a close, relationship to the mandibular nerve, at the junction between posterior and middle thirds, where the mandibular nerve divides into the lingual and inferior dental nerve.

The lingual nerve passes forward, on the medial

side of the cartilage, while the inferior dental lies lateral to its upper

margins & runs forward parallel to it and

terminates by dividing into the mental and incisive branches.

From the proximal end of each cartilage the malleus and , incus two of the bones of the middle ear, are developed; the next succeeding portion, as far as the lingula, is replaced by fibrous tissue, which persists to form the sphenomandibular ligament & the perichondrium of the cartilage persist as sphenomallular ligament.

Between the lingula and the canine tooth the cartilage disappears, while the portion of it below and behind the incisor teeth becomes ossified and incorporated with this part of the mandible.

The mandible first appears as a band of dense fibro cellular tissue which lies on the lateral side of the inferior dental and incisive nerves.

For each half of the mandible, Ossification takes place in the membrane covering the outer surface of Meckel's cartilage and each half of the bone is formed from a single center which appears, in the region of the bifurcation of the mental and incisive branches, about the sixth wk of fetal life.

Ossification grows medially below the incisive nerve and then spread upwards between this nerve and Meckel’s cartilage and so the incisive nerve is contained in a trough or a groove of bone formed by the lateral and medial plates which are united beneath the nerve.

At the same stage the notch containing the incisive nerve extends ventrally around the mental nerve to form the mental foramen. Also the bony trough grow rapidly forwards towards the middle line where it comes into close relationship with the similar bone of the opposite side, but from which it is separated by connective tissue.

A similar spread of ossification in the backward direction produces at first a trough of bone in which lies the inferior dental nerve and much later the mandibular canal is formed. The ossification stops at the site of future lingula. By these processes of growth the original primary center ossification produces the body of the mandible.

THE RAMI OF THE MANDIBLE

The ramus of the mandible develops by a rapid spread of ossification backwards into the mesenchyme of the first branchial arch diverging away from Meckel’s cartilage. This point of divergence is marked by the mandibular foramen.

The condylar cartilage:

Carrot shaped cartilage appears in the region of the condyle and occupies most of the developing ramus. It is rapidly converted to bone by endochondral ossification (14th. WIU) it gives rise to:

Condyle head and neck of the mandible.

The posterior half of the ramus to the level of inferior dental foramen

The coronoid cartilage:

It is relatively transient growth cartilage

center ( 4th. - 6th. MIU). it gives rise to:

Coronoid process.

The anterior half of the ramus to the level of inferior dental foramen

The alveolar process

It starts when the deciduous tooth germs reach the early bell stage.

The bone of the mandible begins to grow on each side of the tooth germ

By this growth the tooth germs come to be in a trough or groove of bone,

which also includes the alveolar nerves and blood vessels.

Later on, septa of bone between the adjacent tooth germs develop, keeping each tooth separate in its bony crept.

The mandibular canal is separated from the bony crypts by a horizontal

plate of bone

The alveolar processes grow at a rapid rate during the periods of tooth

eruption.

STRUCTURES ASSOCIATED WITH MANDIBLE

BLOOD SUPPLY

MANDIBULARNERVE

Largest branch of trigeminal nerve

Mixed nerve with 2 roots

LargeSensory

root

Smallmotor root

INNERVATIONSkinMucous

membraneMandibula

r teeth and periodontal ligament

Bone of mandible

TMJParotid

gland

Masticatory muscles,masseter,temporalis,pterygoideus medialis and lateralis

mylohyoidAnt. Belly

of digastricTensor

tympaniTensor veli

palatine

SENSORY

MOTOR

BRANCHESFrom undivided nerveAnterior division Posterior division

Branches from undivided nerve

Nervous spinosus

Medial pterygoid nerve

Branches from anterior division

Deep temporal nerve

Masseteric nerve

Lateral pterygoid nerves

MOTOR

Buccal nerveor

buccinator nerveor

long buccal nerve

SENSORY

Runs forward under lateral pterygoid muscle

Lower head of lat. pterygoid

Buccal nerve

Buccal nerve

Emerges under anterior border of masseter muscle.

Buccal nerve do not innervate buccinator muscle,facial nerve does.

masseter

Lateral pterygoidmuscles

Deep temporalnerves

Branches from posterior division

Lies medial to lateral pterygoid muscleGives off

1) auriculotemporal nerve

2) lingual nerve

3) Inferior alveolar nerve

Auriculotemporal nerve

Lingual nerve

Inferior alveolar nerve

AURICULO TEMPORAL NERVE

o Traverses upper part of parotid gland

o Crosses posterior portion of zygomatic arch

o Gives off no: of branches

o Communicate with• facial nerve• otic ganglion• anterior auricular branches• branches to external acoustic meatus• branches to TMJ• superficial temporal branches.

LINGUAL NERVE

Run between tensor veli palatine and lateral pterygoid

Reaches lower border of lateral pterygoid

Run between ramus and medial pterygoid

Run anterior and medial to inferior alveolar nerve

Reaches side of tongue behind III molar

INFERIOR ALVEOLAR NERVE

Descends medial to lateral pterygoid muscle

Enters mandibular canal

Inferior alveolar nerve, artery, vein travels through mandibular canal

Exit of nerves, arteries and veins at the mental foramen as incisive nerve and mental nerve

Mylohyoid nerve: Branch from inferior alveolar nerve runs downward and forward along

mylohyoid groove on medial suface of ramus and reaches mylohyoid muscle

supplies skin on inferior and anterior surface of mental protuberance

provide sensory innervation to mandibular incisors and pulpal innervation to mandibular molars.

once it enters the canal-travels anteriorly with inferior alveolar artery and vein.

DENTAL PLEXUS• Serves mandibular posterior teeth • Provide pulpal innervation• Other fibers supply sensory innervation to

buccal periodontal tissues of same teeth

INCISIVE NERVE• Remain within the mandibular canal and form

nerve plexus that innervates pulpal tissues of mandibular first premolar, canine, incisors.

MENTAL NERVE• Exits through mental foramen• Divides into three branches• Innervates the skin of chin , skin and mucous

membrane of lower lip.

Techniques of Mandibular Anesthesia

Mandibular Nerve Blocks

• Inferior alveolar

• Mental - Incisive

• Buccal

• Lingual

• Gow-Gates

• Vazirani Akinosi

Inferior Alveolar Nerve Block

• Not a complete mandibular nerve block.

• Requires supplemental buccal nerve block

• May require infiltration of incisors or mesial root of first molar

Inferior Alveolar Nerve Block

Nerves anesthetized

Inferior Alveolar

Mental

Incisive

Lingual

Areas Anesthetized

Mandibular teeth to midline

Body of mandible, inferior ramus

Buccal mucosa anterior to mental foramen

Anterior 2/3 tongue & floor of mouth

Lingual soft tissue and periosteum

Technique

Apply topical

Area of insertion:

- medial ramus, mid-coronoid notch,

- level with occlusal plane (1 cm above),

- 3/4 posterior from coronoid notch to pterygomandibular raphe

- advance to bone (20-25 mm)

Target Area

Inferior alveolar nerve, near mandibular foramen

Landmarks

Coronoid notch

Pterygomandibular raphe

Occlusal plane of mandibular posteriors

Precautions

Do not inject if bone not contacted

Avoid forceful bone contact

Complications

Hematoma

Trismus

Facial paralysis

Long Buccal Nerve Block

Anterior branch of Mandibular nerve (V3)

Provides buccal soft tissue anesthesia adjacent to mandibular molars

Not required for most restorative procedures

Technique Apply topical Insertion distil and buccal to last molar

Target - Long Buccal nerve as it passes anterior border of ramus

Insert approx. 2 mm, aspirate

Inject 0.3 ml of solution, slowly - 25-27 gauge needle

Area of insertion:- Mucosa adjacent to most distal MOLAR

Landmarks

Mandibular molars

Mucobuccal fold

Mental Nerve Block

Terminal branch of IAN as it exits mental foramen

Provides sensory innervation to buccal soft tissue anterior to mental foramen, lip and chin

Incisive Nerve Block

Terminal branch of IAN     

Originates in mental foramen and proceeds anteriorly

Good for bilateral anterior anesthesia           

Not effective for anterior lingual anesthesia  

Nerves anesthetized

Incisive

Mental

Areas Anesthetized

Mandibular labial mucous membranes

Lower lip / skin of chin

Incisor, cuspid and bicuspid teeth

Vazirani Akinosi

Gow Gates

THANK YOU